Chromatographic apparatuses used for both gas and liquid chromatography typically employ capillary columns to provide control passageways for substances to be analyzed. Areas of analytical application for capillary columns include gas chromatography, liquid microbore chromatography, capillary electrophoresis, and supercritical fluid chromatography. In many analytical applications today, glass, metal or flexible fused silica capillary columns are used. Occasionally, polymeric capillaries are also used.
In many analytical chromatographic applications in which a chromatographic column, such as a capillary column, is employed, the column ends must be connected, e.g., to a sample injector and a detector of a chromatographic device, to another column, etc. Connectors are known in the art for receiving a fluid stream in a first fluid-bearing conduit (such as a column) and then delivering the received fluid stream to a second fluid-bearing conduit (such as may be found in a detector, in a second column, etc.). The fluid connection may be obtained by manual alignment and coupling of separate components that comprise the connector, such as by alignment and compression of a sealing device onto a tubular device while being fitted to a receiving fitting.
The sealing device on conventional connectors is typically a ferrule having a conical frustrum exterior and a through hole. The tubular device, such as a column, or connecting tube, is inserted into the through hole and the tubular device/ferrule assembly is then inserted into a receiving feature, e.g., of an injector or detector or union or fluidic manifold of a chromatographic system, which is shaped as a complementary conical frustrum. The receiving feature is referred to as the ferrule seat. The tubular device/ferrule assembly is then forced into the ferrule seat via pressure, e.g., as may be applied by a threaded fastener, to provide a seal between the ferrule and ferrule seat.
Good laboratory practice dictates that, upon replacement or reinstallation of a column, the ferrule should be replaced. However, replacement is often a difficult or tedious procedure. For example, the ferrule in the connector may have become seized and are difficult or impossible to remove. Sometimes, prying tools or screw extractors are employed in order to obtain sufficient purchase to remove the ferrule from the cavity. In yet other instances, a thermal shock process may be employed to dislodge the ferrule. However, such process can damage the interior of the connector. Thus, a routine column removal, replacement, or installation task becomes an expensive and time-consuming process, which can harm other components of the system, such as receiving elements of injectors or detector of the system.
As such, there is interest in the development of an approach to easily remove stuck ferrules, or analogous structures such as plugs, from connector interiors, such as ferrule seats, e.g., of injectors and detectors in chromatographic systems. The present invention satisfies this need.